拉曼共振四能级原子系统中的有效交叉Kerr非线性  

Effective cross-Kerr nonlinearity in a Raman resonant of four-level atom

作　　者：王利强[1,2] 查新未[2] 李永放[1] 

机构地区：[1]陕西师范大学物理学与信息技术学院,陕西西安710062 [2]西安邮电学院理学院,陕西西安710061

出　　处：《陕西师范大学学报（自然科学版）》2011年第6期27-30,共4页Journal of Shaanxi Normal University：Natural Science Edition

基　　金：国家自然科学基金资助项目(10902083)

摘　　要：提出了利用四能级原子系统与三个电磁场相互作用获取有效交叉Kerr非线性的方案.应用微扰理论和密度矩阵方法,得到了三阶极化率与外加电磁场失谐量的变化关系.结果表明:当两个弱探测场的失谐量达到拉曼共振时,可以获得一个大的交叉Kerr非线性磁化率,且自Kerr非线性极化率和线性极化率为零.证明了在具有拉曼共振的四能级原子系统中获得无吸收有效交叉Kerr非线性的可行性.A theoretical investigation is put forward for obtaining effective cross-Kerr nonlinearity of the four-level atom interacting with three electromagnetic fields.Using density-matrix equations and perturbation iterative method,the variation dependence of the third-order susceptibility on the detunings of the applied electromagnetic fields is derived.The results show that a large cross-Kerr nonlinearity can be generated when the detunings of the two weak probe fields are Raman resonant,and the corresponding linear susceptibility and self-Kerr interactions vanish.The realization of the effective Kerr nonlinearity with vanishing absorption is possible in a Raman resonant four-level system.

关 键 词：非线性光学 三阶极化率 交叉Kerr非线性 拉曼共振 

分 类 号：O437.3[机械工程—光学工程]